I am reacquainting myself with my flash and I understand how the manual flash works, but the manual is unclear as to what the various settings of automatic provide. The dial has five stops that are automatic, but I have no idea of what the significance of the choices are. Anyone have experience with auto flashes and can tell me what the difference is?

Which 45 do you have? There are many models with CT designations or CL designations. I can pull mine out of my stash of film camera stuff (I only used it with my Nikon F3 way back when) and I also needed a special TTL cord to get it to use the camera's TTL metering.

Anyway, there are a few youtube videos (not that helpful anyway) but knowing exactly which 45 model you have can narrow it down.

Just pulled mine out my old flash stuff. Mine is a 45 CT-5. I've got the C60 adapter for the Nikon F3 camera (meaning it fits the specific F3 flash shoe) which also allows it to use the TTL capability of the camera. It was (and is) a great flash for the Nikon F3 film camera, but I would be very wary of using it on a modern digital camera.

Here is a little more information on the different models on the link below. There are some dangers on digital cameras related to voltage when using the hot shoe, instead of the PC cord to the camera body. Before your question I had never thought about this, so you might want to do some research on your specific flash and specific camera.

http://strobeex.blogspot.fr/20...cl1-cl3-cl4-cl4.html

The Auto mode on mine is fairly straightforward. On the top of the flash set the ASA film speed, then turn the larger ring to the f stop you are using, being sure that the aperture you set on the camera/lens is the same as on the flash. You're done. Mine has a distance scale indication, closest to farthest distance usable at that ASA and that f-stop aperture.